The Scientific Resource core is responsible for carrying out a variety of scientific procedures to provide both data and tissue samples to the various projects and to perform overall data management and statistical analysis. The specific functions of this core are as follows: 1) To assign animals in a balance fashion to the three different perfusion groups to ensure an equal distribution of age animals that are cognitively impaired and those that are relatively spared. 2) To conduct MCI and PET scans on all monkeys before perfusion to enable quantitative volumetric and metabolic analyses to be conducted. 3) To conduct all perfusions of monkeys both in Boston and if necessary at Yerkes. 4) To prepare and distribute appropriate fresh or frozen tissue samples from hemisphere of each animal to all of the projects. 5) To cut serial whole hemisphere sections from the other hemisphere of all of the animals and prepare four archival series of stained sections (myelin, thionin, H&E and AChE) for use by all the projects. 6) To conduct and monitor the results of postmortem autopsies on all animals to ensure that there are no occult diseases that could confound our observations on the relationship of age- related changes in the brain to changes in cognitive function. 7) To maintain an integrated database of health records and other data extract from the Yerkes Animal Records System, experimental manipulations conducted by the program and the outcome variables of the different projects and to perform overall statistical analyses of these variables to identify major factors contributing to age-related cognitive dysfunction. 8) To encourage and make available to other investigators both brain tissue and other tissues from our animals that are not needed for the specific aims of this project.